Pneumatic door closer device



April 19, 1960 B, A, QU|NN 2,932,847

PNIUITIC4 DOOR CLOSER DEVICE Filed NGV. 19, 1956 IN V EN TOR. ew. @am

PNEUMATIC DOQR CLGSER DEVICE Bert A. Quinn, St. Paul, Minn.

Application November 19, 1956, Serial No. 623,109

2 Claims. (Cl. 16-66) My invention relates to improvements in pneumatic door closing devices and more particularly to improvements in expansible and retractable devices of this character such as disclosed in my Patent 2,646,589, dated July 28, 1953.

When devices of the character immediately above described are used in connection with light weight doors, such as those formed from light weight metals, as aluminum, the force of the coil spring within the cylinder (working against the compressed air being released through the check valve) causes such a rapid swinging movement to be imparted to the light Weight door during closing movements thereof that an undesirable bouncing movement is imparted to the door during its final closing movements.

' This is due not only to the light weight character of the door but also to the fact that whereas the coil spring exerts an increasingly greater bias on the door as it is swung toward its maximum opened position, said coil spring exerts decreasingly less bias on the door as it approaches a closed position.

The primary object of my invention is the provision of a device of the class immediately above described wherein means are provided for eliminating the bouncing or rebounding action of the door during its final closing movements.

A further object of my invention is the provision of means, whereby the decreasing yielding bias of the coil spring during final door closing movements, is supplemented.

A still further object of my invention is the provision of means whereby the increasingly greater yielding bias exerted upon the door by the coil compression spring during opening movements thereof partially offset during nal door opening movements.

A still further object of my invention is the provision of a novel arrangement of parts whereby yielding means interposed between the door and the door closing pistoncylinder (and Working at substantially right angles to the coil spring within the piston) creates constant but variable friction between the connecting rod and the end of the cylinder in which it is'slidably mounted, whereby to effect steadying movements to the door throughout its entire range of closing movements.

A further object of my invention is the provision of a device of the class immediately above described, which is relatively inexpensive to produce, which has a minimum of working parts, which is rugged and durable in construction and which is foolproof in its operation.

The above Vand still further objects of my invention will become apparent from the following detailed specification, appended claims and attached drawing.

Referring to the drawing, wherein like characters indicate like parts throughout several views:

Fig. 1 is a view in transverse section of a door frame and cooperating door, showing my novel construction in top plan attached thereto, and

i United States Patent Ox 2,932,847 Patented Apr. 19, 1960 ICE Fig. 2 is an enlarged fragmentary view in section, as seen substantially from the line 2-2 of Fig. 1.

Referring with greater particularity to the drawing, the numeral 1 indicates in its entirety a door frame, to which a door 2 is hingedly secured, as at 3.

The spring-operated pneumatically-controlled door closer, herein broadly referred to as an extensible and retractable device, includes an elongated tubular cylinder 4, a piston or plunger rod 5, a piston or plunger 6 mounted fast on the inner end of the plunger rod 5 within the cylinder `4, and a coil compression spring 7 which is compressed between the piston 6 and inner end 8 of the cylinder 4 in which the plunger rod 5 is slidably mounted for extending and retracting movements.

The construction of the cylinder 4, the piston 6 and immediately associated parts, including suitable means for controlling the escape of air from the outer end 9 of the cylinder 4, during retracting movements of the rod 5, form no part of the instant invention and hence will not be explained in detail here. It suffices to state that a suitable arrangement of such parts is disclosed in my Patent 2,646,589, above referred to.

The projected end of the rod 5 is pivotally secured to` A leaf spring 12 extending generally longitudinally of the cylinder 4, in side by side relationship thereto, has its inner end rigidly secured to the cylinder 4 by any suitable means such as by a rivet 13 passing therethrough and through a reinforcing collar 14 extending circumferentially thereof intermediate the ends 8 and 9. It will be noted that the inner end of the rivet 13 projects through the wall of the cylinder 4. Preferably the connection 13 between the leaf spring 12 and the cylinder 4 is axially inwardly of the path of travel of the piston 6, so as not to interfere with said piston, see particularly Fig. 2.

Preferably and as shown in Fig. 1, the leaf spring 12 projects longitudinally outwardly of the cylinder 4 beyond the outer end 9 thereof and thereat is provided with means, such as screws, for detachably but rigidly securing same to the door 2, as indicated at the numeral 15. By the novel arrangement above described, one has a primary spring means, namely the coil spring 7, which Vexerts a yielding bias on the cylinder 4 and piston 6 generally longitudinally thereof to impart retracting (door closing) movements thereto, and a secondary spring means, namely the leaf spring 12 which exerts a yielding bias on the cylinder 4 and piston 6 carried thereby at right angles to the longitudinal dimensions thereof in the direction of the door 2. Up to a point, the primary spring i and secondary spring 12 both exert an independent yielding bias upon the door 2 to move same toward the'closed full line position of Fig. l upon the hinges 3, the coil spring 7 exerting a progressively greater bias as the door 2 approaches its maximum opened position.

This point is reached at dead center with respect to connections 3, 11 and 15. Beyond this dead center position, the action of the leaf spring 12 is reversed and consequently through connections 3, 11 and 15, said leaf spring 12 exerts a yielding bias on the door 2 in a direction opposite of that exerted by the coil spring 7, namely in a direction to impart opening movements thereto. This yielding bias offsets to a degree the progressively increasing bias of the coil spring 7 to impart closing movements to the door 2. Thus, when the door 2 is released at this point, its initial closing movements are not objectionably rapid and violent (as is customary in devices of this character) but rather are slow and gentle.

Furthermore, as the door 2 approaches the full line closed position, `the bias exerted by the coil spring 7 becomes progressively less. A`t this point, the leaf spring .12 acts as a booster to totally overcome the rebounding or bouncing action o'f the door 2 as the air within the closed end 9 'of the cylinder 4 is compressed.

.Another feature of importance is as follows: The leaf spring 12, working at substantially right angles to the cylinder 4, creates constant but variable friction between theconnecting rod S and the head 8 of the cylinder 4 in which it is slidably mounted. This is clearly illustrated in Fig. l of the drawings. As shown by the intermediate relatively long broken line showing, the friction between the connecting rod S and head V3 is greatest at this intermediate position of the door 2 because of Vthe greater angularity between the cylinder 4 and door 2. This fric tion becomes less as the door 2 approaches either the extreme .open (illustrated by the relatively small dottedV lines) position, or the closed position, shown by full lines. This frictional engagement imparts steadying movements to the door 2 during its entire closing move- ,ments, Yand is also a factor in the eliminating of the bouncing or rebounding action of the door 2, as it approaches its closed position. Y

My invention has been thoroughly tested and found Vto be completely satisfactory for the accomplishment of the above objects and while I have disclosed a preferred ernbodiment thereof, it should be specifically understood that same is capable of considerable modication without departure from the scope and spirit of the appended claims.

What I claim is: 1. In a device of the class described, a tubular cylinder, a pistonmounted for reciprocal movements in said cylinder having a push rod projecting from and slidably mounted in rone end of the cylinder for extending .and retracting movements, a coil spring within said cylinder yieldingly biasing said piston in a direction to retract said push rod, means for pivotally securing the projected outer end of said push rod to a door frame on anraxis parallel to the axis of swinging movements of a cooperating door in said frame and in linwardly spaced relation to said door, a at leaf spring in generally side by side relation to said cylinder and extending generally longitudinally thereof for at least one half-the length of said cyiinder, means for detachably securing one end of said leaf spring to the door in face to face relation therewith adjacent the opposite end of said cylinder, and means rigidly securing the opposite end of said leaf spring to the intermediate portion of said cylinder, the inward spacing of the push rod pivot axis from said door when said push rod is pivotally secured to said door frame disposing said opposite end of the leaf spring in spaced relation to said door to impart a curve to said leaf spring when said leaf spring is secured to the door, whereby said leaf spring yieldingly urges 'said cylinder toward the door.

2. The structure dened in claim l in which the means for securing said leaf spring to the door is longitudinally outwardly spaced from the other end of said cylinder and in which the connection of said leaf .spring to said cylinder is intermediate the central portion of said cylinder and said one end thereof.

References Cited in the le of this patent UNITED STATES PATENTS 

